Cellar in a house with a strip foundation: basement construction technology

The main types of strip foundation

The service life of a strip foundation support depends on the type of material used and the operating conditions. On average, these data can be represented as follows:

• foundation poured from monolithic concrete or cement-based rubble - 130-150 years;
• brick strip foundation - from 30 to 55 years;
• prefabricated strip foundation from blocks - from 50 to 75 years.

Design features divide all strip foundations into 2 large groups:

• monolithic, performed at the construction site of the house;
• prefabricated, the support device for which is made from ready-made factory reinforced concrete blocks installed on concrete cushion slabs. The design of this type of foundation is shown at the beginning of the article.

The degree of load on the support divides the strip foundation structures into buried and shallow ones. The cost of building a shallow foundation is only 15-17% of the price of the house

It is also important to understand that the cost of the foundation will increase significantly if the house is on a slope. In this case, the cost may increase significantly.

Therefore, you need to take this into account in advance even at the stage of choosing a site for construction.

Shallow strip foundation

The choice in favor of a shallow strip foundation is justified if the future house has a small mass, for example, it is erected from wood or aerated concrete. The depth of such a support rarely exceeds 70 cm; on average, it is deepened by 50-60 cm. This depth is sufficient to withstand minor loads from light buildings. However, the shallow depth of laying can become a stumbling block when using a shallow strip foundation on heaving soils, since the force of frost heaving can exceed the load from the structure, as a result of which the base can collapse. The device of such a base is shown in the diagram below:

Recessed strip foundation

The construction of houses with heavy ceilings, typical of brick houses, on heaving soils requires a buried strip foundation. Designing a basement garage or spacious basement is another argument for recessed support. Installation is carried out below the freezing point of the soil by 25-30 cm, so that the forces of frost heaving cannot exert pressure on the foundation from below. Under the inner walls, a depth of 45-60 cm is possible. Therefore, on average, such a tape will be mounted 1.5-2 meters below ground level. The value of the freezing depth is a known value that differs depending on the region of the country and is selected from reference books.

The height of the tape above the ground can vary widely depending on the project and the climatic conditions of the area. As a rule, it is selected within 40-60 cm.

The laying of strip foundations is carried out in the warm months of the year, and the presence of a concrete mixer and means of small-scale mechanization will greatly facilitate the process. This is a significant advantage of this type of foundation, for example, over USHP, where it will not be possible to pour such an amount of concrete on your own.

DIY construction of a strip foundation with a basement

For an independent basement device using a strip foundation, the most difficult moment is the installation of formwork panels.

In general, you need to understand that the possession of minimal skills is necessary to perform any job. The construction of the foundation of the house is considered the most crucial stage, therefore, thoroughness and thoroughness are required in the work.

Build a basement with your own hands

Calculation and preparation

You should not independently calculate the load on the foundation without special knowledge. The thickness of the walls should correspond to the design, as well as the height. It is necessary to calculate the number of boards for the formwork device, the need for reinforcement and the required volume of concrete mixture in advance.

The starting point of calculations for independent work should be a sketch of the foundation with the exact dimensions of the tape:

1. The total area of ​​the enclosing formwork panels is equal to: the outer perimeter of the house X the height of the wall X 2, plus 10% for spacers, stops, screeds.
2. The need for reinforcement is calculated individually, depending on the expected load on the foundation. The reinforcement frame must be made in the sketch, not forgetting about the different thicknesses of the main rods and connecting elements.
3. In the section on the sketch of the strip foundation, there must be at least three pairs of reinforcing bars laid along the perimeter of the basement.
4. The need for concrete mix is ​​equal to the volume of the inner space of the formwork + 5% for losses.

Before construction, it is necessary to plan the correct storage of materials at the construction site, equip the entrance and free access to the pit. Do not make concrete yourself, especially in large quantities.

Concrete mix prepared in artisanal conditions can never be compared in quality with prefabricated concrete. The best solution would be to order concrete from the factory with delivery by a mixer. From the point of view of the quality of the foundation, the entire volume of concrete should be poured at a time.

Layout and earthwork

The foundation is marked at the bottom of the pit according to the rules for constructing rectangles on a plane. Pegs-beacons are hammered in the corners, then a cord is pulled along the outer perimeter.

Parallel and similar to the external one with an inward displacement by the wall thickness, the internal perimeter is indicated. The correctness of the division is determined by the equality of the diagonals of the rectangles.

From the outside, it is necessary to ensure work on the subsequent waterproofing of the monolithic strip foundation, to prevent the soil from falling into the pit.

Formwork and reinforcement cage

Formwork panels are made outside the pit

When manufacturing, special attention should be paid to the absence of gaps between the boards. Usually a board of 20-25 mm is used, a bar for ties and stops 40x40, 50x50 mm

Work progress:

1. The outer perimeter shields are lowered into the pit and pre-fixed.
2. The frame reinforcement is installed and tied with a knitting wire.
3. The shields of the inner perimeter are lowered.
4. The formwork is set exactly in size, the inner and outer shields are knocked down from above with crossbeams.
5. From below, the shields are fixed against spreading by wedges, in height - by stops from the outside, which rest on stakes driven in at a distance.

All ties and stops are rigidly fastened with nails or self-tapping screws. In the fastening, it is better to overdo it and hammer in an extra emphasis than to allow the formwork to disperse while receiving concrete.

Stripping, waterproofing and backfilling

The concrete is poured evenly over the entire belt to the full formwork height. The minimum setting time for the mixture is 7 days. Stripping should be done evenly, removing stops and ties. Do not hit fresh concrete. The shields are carefully removed and removed from the pit.

After the final drying of the concrete from the outside, the surface is coated with a continuous layer of bitumen mastic. The bitumen is glued with an overlap of roofing material or roofing felt with a continuous carpet in one direction. After drying on top of the glued layer, the second is similarly applied, but perpendicular to the first.

After the waterproofing of the foundation tape is completed, the soil is backfilled.

For additional waterproofing, you can use a thick solution of ordinary clay instead of filling the outer sinuses with soil. If you fill the sinuses with such a solution, a clay lock is formed, ensuring that there is no water in the basement.

Strip base or slab?

A building with a basement or cellar needs a recessed base

When determining the required depth, it is important to take into account not only the characteristics of the house, but also factors such as the level of groundwater and the characteristics of the soil. Such calculations are usually carried out by professional builders.

When all the calculations have been made, a choice is made in favor of one or another version of the foundation.

The most popular options for houses with a basement are:

1. Strip foundation. It is convenient in that it can be erected from various building materials, prefabricated structures or a monolith. To select certain materials, an accurate calculation of the foundation is carried out, taking into account such a parameter as the load from the house.
2. Reinforced slab base. The strip foundation has a serious disadvantage - it is unable to correctly distribute the load coming from the bearing walls on some types of soil. If you are building a house on problem ground, you should give preference to a slab base. It can be poured entirely on a selected area or equipped with individual slabs.

The strip and slab foundations differ not only in the materials used, but also in the price. The latter has a higher cost, which is fully justified when building a house with a basement on difficult ground. Peat bogs, clay and heaving soils are considered problematic. They are characterized by instability and high groundwater content. Because of this, they are subject to natural shrinkage and periodic movement. A regular foundation will not be able to provide the necessary protection to the house, while a slab foundation has a large area for load distribution and guarantees the stability of the building.

This is especially important for a home with a basement.

Future basement.

Deepening the basement below the foot of the foundation

The desire of the owner to use any space in the house often becomes the reason for the desire to deepen the basement. This allows you to get an almost complete usable area, which can be used for a variety of purposes. However, when carrying out work, several features characteristic of basements should be taken into account.

Basement deepening technology

Before starting work, you should decide on the possibility of their implementation and the technology used.

The fact is that not every type of building foundation allows the basement to be deepened to such a level that the height of the room becomes suitable for full use.

For example, a base in the form of a monolithic reinforced concrete slab does not allow for violation of integrity, since this will negatively affect the load-bearing capacity of the structure and can lead to sad consequences for the entire structure.

Deepening the basement

The easiest way is to deepen the basement in the event that we are talking about the strip foundation most common for private residential buildings. In this case, it is necessary to take into account several significant points related to the technology of production of such works, which are carried out in the following sequence:

Dismantling the existing floor and dredging to the required level. From a technological point of view, these works are not serious difficulties, however, they are carried out in cramped conditions and therefore are very labor-intensive;

Reinforcement of the foundation sole: The additional load on the base forces the reinforcement of the foundation structure. For this, various methods are used, the most popular of which are two: the device of external piles, pressed into the ground below the new floor level, and the creation of a special sheet pile wall, which is also deepened one and a half to two meters from the floor level;

Additional waterproofing.A set of measures aimed at protecting the base of the building, as well as the walls and floor of the basement from groundwater deserves a separate and careful consideration.

The importance of high-quality waterproofing is beyond doubt, as it directly affects the durability of the entire building. Works can be performed using various materials and technologies;

The device of sand filling under the floors. At the next stages of work, as a rule, the standard technology of creating floors is used, which begins with sand filling;

Sand cushion device

Pouring concrete floors and basement walls. The technology of production of monolithic works is similar to that used in new construction. When they are carried out in an existing building, the need for additional costs associated with the constraint factor should be taken into account.

The final stage of work, allowing to make a deepening of the basement, is the finishing of the renovated premises. It is also performed taking into account its characteristics. At the same time, the choice of materials largely depends on the efficiency of the basement ventilation system and the reliability of the waterproofing produced.

Basement and water table

A well-made basement waterproofing is of key importance for the quality of the work under consideration. A decision on the possibility of deepening the basement should be preceded by a study of the depth of groundwater placement.

The easiest way to do this is to dig a hole in the immediate vicinity of the building to the mark of the proposed location of the basement floor, and then observe whether water appears at its bottom or not. Another option is to get information from neighbors who have basements in their houses.

Base reinforcement scheme and basement floor arrangement when deepening to 30 cm

Various waterproofing technologies are used to create protection against groundwater.

The most effective and therefore often used today is considered to be pasting the walls and floor of the basement with two layers of roofing material or roll material similar in performance.

This prevents the ingress of moisture from the ground into the basement, which would lead to unpleasant consequences in the form of the appearance of fungus, condensation, rot and the gradual destruction of building structures.

High-quality basement waterproofing, which you can order from our company, is a prerequisite for deepening work. Moreover, it is carried out regardless of the identified groundwater level and must be included as an important part of the design documentation for the planned work ..

Preliminary work before construction

The study of the site is carried out in the course of engineering and geotechnical surveys

, for which specialists from design organizations are involved. In order to save money, you can do it on your own and carry out studies of soils and hydrogeological conditions of the area on your own. A good result is given by interviewing neighbors and inspecting their cellars or basements.

In the course of studying the conditions of the site, you should pay attention to the following points:

• soil composition, depth of soil layers, tendency to accumulate moisture and heaving;
• the level of groundwater and the height of their rise during the period of melting snow or intense precipitation;
• average depth of soil freezing.

These data will be necessary in the process of choosing the type of cellar that is most optimal for the given conditions and the method of its construction. Experts use the obtained data in the process of carrying out design, calculation and estimate work. The best option for a homeowner is, without a doubt, an under-house cellar with internal access. It is better to lay such a structure even at the construction stage.An option is also possible with the construction of a buried structure during the reconstruction process, but it is quite troublesome and time consuming.

Small cellar

Cellar design basics

A country house with a basement equipped for storing supplies is being built taking into account the requirements of SNiP 31-02-2001 and SNiP 2.08.01-89, as well as RSN 70-88. The regulatory documents define the geometric dimensions of residential and office premises

When equipping cellars, special attention is paid to the issue of waterproofing the walls and floors of buried storage facilities, as well as the necessary air exchange

During the design work, it is necessary to provide for a ventilation system. In most cases, a vertical duct with an external chimney is sufficient. This method of air exchange does not require complex equipment and any operating costs.

Cellar ventilation device diagram

The cellar in a private house is designed taking into account the total size of the building

When making calculations, the following points should be taken into account:

1. The storage facility is recommended to be located near the geometric center of the building with equal distance from the outer contour of the foundation.
2. The depth of the cellar is selected taking into account the level of groundwater and the degree of their seasonal fluctuations.
3. In the process of design activities, such a factor as the composition of the soil must be taken into account.

The central location of the cellar minimizes the influence of temperature fluctuations due to the cooling of the soil masses and their freezing during the onset of cold weather. It is good if the entrance to the office premises is directly from the house - this will significantly reduce heat loss. For the convenience of residents, it is recommended to install a stationary staircase with a march slope of no more than 45 ° and a step width of at least 200-250 mm.

Drawing and scheme for the construction of the simplest cellar under the house

Cellars are classified, first of all, according to the degree of their burial, which, in turn, depends on the level of fluctuation of groundwater:

1. Underground structures are built when water strata occur lower than 3-3.5 m or under houses located on a hill.
2. A semi-buried cellar is erected at a depth of soil water no more than 0.8-1.2 m from the surface.
3. Above-ground storage facilities are constructed in areas where there is no possibility and use of underground or semi-underground premises due to the high probability of flooding.

Types of basement designs

The foundation of the house can be monolithic or tape. The first option will cost more, since it requires a large consumption of reinforced concrete. Determines the choice of foundation structure soil condition. Experienced design geologists should give recommendations based on the results of soil studies at the construction site. We strongly advise you to contact specialized design organizations to get an opinion on a particular type of foundation that is applicable to your site.

Strip foundation

Differences in the construction of the foundations are also determined by the material chosen for its construction. Let's consider the most common types:

1. Monolithic reinforced concrete. Foundation walls are constructed of concrete mortar reinforced with metal structures. This type of foundations is very reliable, suitable for most types of soils, but with significant deepening, it requires good waterproofing. The strip foundation is erected from concrete. It should be poured into the formwork, which must be prepared to the full height of the walls of the structure. Their width should exceed the thickness of the house wall by 0.2-0.3 m. A frame made of reinforcement is installed in the formwork, after which it is poured with mortar. It is recommended to use M500 grade cement. All this can be done with your own hands if you carefully follow the project and building codes.
2. Concrete blocks. In this case, it will be more difficult to do everything with your own hands, since it is very problematic to lift concrete blocks even together.The use of equipment, at least a hoist or a winch, will be required. But the construction speed is much higher. The blocks are laid in accordance with the project and fastened with mortar. For reliability, they must be pulled together with wire. The disadvantages include the need for increased waterproofing, especially if the basement is deep enough and the groundwater level is high.
3. Brick foundation. For the construction of foundations, a special brick is used that does not allow moisture to pass through. When erecting walls, with a step of 0.4 m, it is necessary to make a tape belt of concrete with reinforcement, which will strengthen the structure. The upper part of such a foundation is also constructed of concrete.
4. Foam concrete blocks. An option similar to the previous one, but faster, and, unlike the use of concrete blocks, does not require the use of technology. Of the structures described, the most economical type of foundation. It is quite suitable for the DIY construction method.

Monolithic foundation of a house with a basement

Deepening the basement below the foot of the foundation - DIY Handbook

Placement of the sauna in the basement of the house

In a suburban individual residential building, the basement significantly increases the usable area of ​​the building. Such a space is rarely empty.

Since an individual house can be safely called an autonomous structure with utilities, heating boilers, storage water tanks, it is best to place them in the basement.

A workshop, a pantry with winter storage with easy access will be a great example of a basement use. Sometimes, if there is enough space "underground", you can arrange a garage, a bathhouse, or even a gym.

Conditions for construction

Photo of a trench for a strip foundation in a cellar

The cellar, in contrast to the traditional basement, has a smaller size, and its construction can be carried out after the construction of the house. The device of such a room inside the existing housing is possible only if the building is located on a strip foundation. In houses with a monolithic slab, the construction of a cellar is impossible. In such cases, subfloors are equipped only outside the foundation of the house, for example, in annexes.

To reduce heat loss, the entrance door of the cellar must be insulated. Above the cellar, it is desirable to have a structure, such as a barn or a transition room, so that there is a possibility of ventilation and drying of the basement. For constant ventilation and maintaining the microclimate, you need to make special holes and niches in the walls.

It is best to build a cellar in the summer season, since the groundwater during this period is at a relatively low level, and the amount of precipitation is minimal.

How to build a solid foundation with your own hands: tips and instructions from professionals (81 photos + video)

The basis of any structure is the foundation. The stronger and more correct it is installed, the longer any building will serve.

Therefore, in order to save a budget, many people want to know: how to make a foundation with their own hands.

First you need to choose the type of foundation, because there are several types of them: strip foundation, columnar, pile and slab options. How they differ from each other, we will tell below.

The most versatile and commonly used type of building foundation is strip foundations. It cannot be used only in permafrost and for structures “on the water”.

Such a foundation is suitable for any building and allows you to build a high-quality basement or basement.

The main disadvantage of this type of foundation is the large amount of earthwork and building materials.

For small buildings, in order to save materials, it is recommended to use a columnar foundation. It allows you to deliver a high-quality base for an easy building with less time and effort.

You can build supports from brick, concrete, or even wood (only resistant to decay - larch, for example).The depth for the pillars is chosen taking into account the material and type of soil.

After installing all the supports, you need to tie them into a single system for greater strength.

The disadvantages of the foundation can be called the impossibility of the basement foundation. The base is not suitable for heavy buildings, unstable soil also precludes its use.

The foundation of a house on stilts looks like a columnar foundation, but it is not. The main difference is the depth of the supports. Due to its small diameter, in comparison with the pillars, the holes for the piles are not dug, but drilled. This allows the supports to be installed at greater depths and dug into more stable rocks.

Otherwise, the technology for placing and strapping the supports is identical to the columnar foundation.

The main disadvantage of this foundation is the use of special equipment. Recently, however, piles with a screw at the end began to appear, which allows them to be screwed, like a self-tapping screw, into the rock. This is what made the piles accessible to the layman.

One of the most rarely used types of foundations. Reinforced slabs are more commonly used for roads and boulevards, but some people also use them as a base for a house.

To create it, a gravel-sand cushion is first poured, after which reinforcement is placed and the foundation is poured. It turns out a "floating" base for the house.

Plus such a basis - independence from the type of soil and its freezing in the winter.

Now let's talk in detail about creating a strip foundation, as the most common and versatile in construction.

And here we will make an important clarification. It is best for a specialist to independently calculate these parameters.

The fact is that it depends on the correctly calculated depth and width of the base whether or not the future building will withstand the foundation, and therefore your life.

• Mark the territory.
• Carry out earthworks (dig trenches).
• Create a sand and gravel pillow.
• Make a formwork for the foundation.
• Lay the future foundation with a belt of reinforcement.
• Provide ventilation (if necessary) using pipe sections.
• Pour concrete.
• Smooth the surface until solidified.
• Remove the formwork after a week.
• After another 3 weeks, the concrete will completely harden and waterproofing can be done with roofing material and hot bitumen.
• Lay the basement on top of the concrete with a brick and make waterproofing.

The foundation is ready!